Thomas prosser



UNITE Ic sTATEs PATENT oEEicE.

THOMAS PROSSER, OF NEW YORK, N. Y.

SURFACE CONDENSER.

Specification forming part of Letters Patent No. 18,861, dated December 15, 1857; Ressued May 22, 1866, Nos. 2,254 and 2,255.

To all whom t may concern Be it known that I, THOMAS PnossER, of the city and State of New York, have invented a new and Improved Surface Condenser for SteainEngines; and I do hereby declare that the following is a full and eX- act description thereof, reference being had to the accompanying drawings and to the letters of reference marked thereon.

My condenser consists of two hollow slabs 7 (and for which hollow slabs a Patent, No. 10,450, was granted to me January 24, 1854) or chambers, or their equivalents, communicating by means of annular spaces with each other', such annular spaces being formed by means of tubes, one within the other, the inner ones passing quite through both chambers, while the outer ones merely enter into them. And, I by preference, combine three such condensers, each in its own cistern, to form one complete condenser or condensing apparatus.

The bottom cistern first receives the cold condensing water while the distilling condenser therein, receives the vapor of a portion of that same water, after it has become sufficiently heated by passing through the cistern of the main condenser. Each of these two condensers have a pipe from their low est part, through the bottom of their respective cisterns, from which the water is drawn by means of two pumps and which force it through the upper or lieatencondenser into the boiler.

The cistern in which the heater-condenser is placed, first receives the exhaust steam from the engine, and thereby the water within the heater-condenser has its temperature increased while the uncondensed steam passes into the main condenser together with the water resulting from condensation.

All the steam which has become condensed before entering the apparatus, together with any filth that may accumulate in the eX- haust pipe is collected in a vessel or catchpit below it and goes to waste.

The air contained in the two internal condensers is allowed to escape through a pipe from the bottom of each, and in the case of the main condenser a stop-cock is necessary for closing the same when working under pressure and thereby (when the condensing water is properly limited) causing the water in its cistern to boil suiiiciently to supply the distilling-condenser with vapor for condensation to make up for waste and other purposes. In conjunction with this is a stopcock to regulate the quantity of exeunt hot condensing water which shall be allowed to escape; the rest escapes in a colder state from some lower part of the apparatus.

It will thus be seen, that, the main condenser as well as the distilling-condenser are both internal condensers of the steam and vapor, the former from the engine and the latter from the hot-well or main cistern, while the heater-condenser acts upon the stfeam externally to condense only a portion o it.

IVhen the exhaust steam is free to escape into the atmosphere through the condenser, its temperature will scarcely exceed the boiling point and consequently the water in the heater-condenser can never reach it, much less can that in the main condenser, even when there is a decient supply of water for condensation. The working under a pressure within the condenser has therefore for its object the supplying of feed water at a high. temperature and vapor from the hot well of a sufficient elasticity to force itself in sufficient 'volume into the distilling-condenser below.

Of course the apparatus admit-s of a variety of modilications without altering its main features, but the method of combining the three condensers as herein set forth appears the best.

But that the nature of my invention and the means which I adopt of carrying the same into effect may be fully understood, I will proceed to describe the drawings anneXed, first premising that the same marks of reference refer alike to similar parts in each figure.

Figure l, is a front elevation of the two cisterns l and 3 containing the distillingcondenser and the heat-er-condenser, behind which is the main-condenser cistern 2. Fig. 2, is a vertical section through the center of Fig. 1, on the line A, that is to say, through the distilling-condenser, main-condenser and heater-condenser, together with the cisterns l, 2, and 3 inclosing them. Fig. 3, is also a vertical section through the main condenser 2 and the cistern 2 which contains it, 0n the line marked B, Fig. 2. Figs. 4;, 5 and 6, are horizontal sections through the foregoing Figs. l, 2 and 3 and on the lines marked respectively C, D and E.

and of the vapor within the other.

The condensers 1, 2 and 3 are each composed as follows, in which a, a, are the hollow slabs or chambers, Z7, b, the tubes connecting the top of the one with the bottom of the other, and c, c, the tubes passing through the tubes Z, as well as through the hollow slabs or chambers a, a, forming annular spaces CZ, CZ, within which nothing but steam and vapor (note, by steam I mean t-he eduction or exhaust steam from the engine, and by vapor that from the cistern of the main condenser) or the water resulting from their condensation is allowed to enter.

e, is a pipe from the top of the cistern 2 to convey the vapor into the distilling-condenser 1 at the bottom of which a pipe e collects the results in water, through the bottom of the cistern 1 containing it; and in like manner e is a' pipe from the bottom of the main-condenser 2 and through the bottom of the cistern 2 containing it, for the purpose of collecting the water resulting from t-he condensation of the steam within the one Each pipe must have a'separate pump to d-raw off the water, but one pipe f may receive the discharge of both and convey it into the heater-condenser 3; outside of which and within the cistern 3 containing it, the clean exhaust steam first enters (having deposited all filth, together with the steam previously condensed in the catch-pit Z1, from which it is blown off at intervals through the cock b) by the pipe g. The exhaust steam after acting upon ythe heater-condenser 3 will have some portion condensed and this is prevented from returning, by the pipe g being continued higher than the holes g', g

and therefore the whole escapes together through the holes g', g into the main-condenser 2 where the water which surrounds it is supposed to be boiling and is contained in the cistern 2.

As the exhaust steam after it has left the cistern 3 is still hot enough to boil the water in the cistern 2 it is of course hot enough to produce a higher temperature in the heatercondenser 3 through which the feed-water is forced into the boiler through the pipes n, and At the bottom of the main-condenser cistern 2 the water is much colder than at the top and of course the steam is also colder and has become water yin consequence of condensation. This water is nevertheless collected at a high temperature and through t-he medium of the pipe f as before stated pumped together with that from the distilling-condenser 1 into and through the heater-condenser 3 into the boiler.

z' is a pipe from the bottom of condenser 1 to allow of the escape of air technically called blowing through, or the same may be effected through the pipe e. j is also a blow-through-pipe to displace any air that may be in the main-condenser 2 as also to enable the engine instantly to assume the character of a non-condensing high-pressure one. In fact it will assume that character automatically when the operation of the condenser 1 is not required and the cock 7c is open in consequence of derangement to t-he cold water pump or a deficient supply of condensing water. (Note, the cock 7a is only required, absolutely to be shut when a supply of water for waste is required from the condenser 1.)

Z is the waste pipe .upon which a cock Z is placed to regulate the amount which shall be allowed to flow from the cistern 2 between the lines marked high water level and low water level, the latter being produced by the pressure of the superincumbent vapor above the water, but lower than this the water must not be allowed to go, because the whole of the condensing water will then make its exit through the pipe m into Z beyond the point where the cock Z has any control as it is entirely open. The cock 7c being shut therefore, the cock Z fully controls the temperature and consequent pressure of the vapor in the cistern 2 by admitting the whole of the condensing water to pass off through (for none will pass by the pipe m, when Z is open, in consequence of the column of water in m being so much heavier than that connected with the pipe Z) its ample capacity, or only a portion thereof.

The proportional surface of each condenser will vary with circumstances, but ordinarily it is presumed that the distilling-condenser and the heater condenser each having from one tenth to one fifth as much surface as the main-condenser will give excellent results, when the steam boiler pressure is from to 100 lbs. to the square inch and cut off at from one'half to two thirds of the stroke of the engine.

rlhe temperature of the feed-water will probably be on the average about 16 to 18 above that of the exeunt hot condensing water andthe same below that of the exhaust steam as it enters the heater-condenser cistern 3. This high temperature is obtained in consequence of the small capacity of the annular condenser into which the exhaust steam is expanded, after having expanded first in the cylinder and next in the heatercondenser cistern 3. The reason why so lit tle difference of temperature is anticipated t lies in the fact of water at high temperatures, absorbing heat far more rapidly than at low temperatures, and particularly when in a state of violent ebulition, for it may be observed, that, water when heated to a less temperature thanl that necessary to produce ebulition, absorbs heat very slowly and of course very little can escape as vapor, but the moment 'violent ebulition commences the absorption is very rapid as is evinced by the sov copious discharge of vapor. The absorption of caloric must be in proportion to its evolution and as vapor contains in the same weight about six times as much as in water at the same temperature, it is probable that the same proportion holds good with regard to the amount of caloric absorbed. Leslie asserts that water at 212' conducts heat live times more rapidly than it does at about 32; and Parks made some experiments which went to show that hot water abstracts heat faster than iron will allow it to pass through, in the proportion of 26 to l0, but the culinary phenomenon of a boiling tea-kettle, shows that the caloric will pass through the metallic bottom, apparently without aHecting it at all, nay even its temperature will become reduced, inasmuch as the hand may be borne against it when the water boils but not before.

I would observe, that, simultaneously with the entrance of the condensing water into the cistern l, the exhaust steam enters cistern 3, the latter passes through the holes g g into the condenser 2 while the condensing water somewhat raised in temperature passes from the cistern l into the cistern 2 and consequently, outside of the condenser 2 wherein the steam becomes condensed. At the same time the vapor from cistern 2 enters condenser l and becomes condensed also. Then both commingle and are forced through the heater-condenser 3 into the boiler.

In starting the engine the cock 76 should be left open for a few minutes to allow the air within the main-condenser to escape, or it may be left open until necessary to close it in order to supply water to make up for the waste. If a moderate quantity only is required the cock Z may be left open, but if more is required it may be partially shut, which will increase the temperature of the vapor in proportion to the depression which it produces upon the surface of the water which must never be allowed below the low water line.

Now it may be proper to observe, that, in consequence of the small portion of the condensing water which is required to be evaporated to supply the waste there is no probability of the saturation being sufficient to cause a deposit upon t-he condenser to an injurious extent, far less than must have occurred had the same water been used in the boiler wherein all the solid matter contained in the water must necessarily be deposited. Ordinary lime waters will however coat the condenser with carbonate of lime, which is readily removed, and once in one year will be quite sufficiently frequent. In the case of sea water however the ordinary deposit is sulfate of lime, but as this does not deposit until the water is nearly saturated and the temperature amounts to 217 F. it is not contemplated that any dificulty will arise from this deposit which is so ruinous to sea going Steamers. These facts were developed by Tarady nearly 30 years ago, but this is the only practical embodiment of them to the purposes of the economic working of the steam-engine known to the writer.

In case of accident or non-supply of condensing water, the water should be run out at the cistern l and the cock la being open the engine will work as a common non-condensing engine and the boiler may be supplied with feed water by means which will readily suggest themselves. If however the hand-holes in the main-condenser cistern are removed so as to allow a free ingress and egress of air, a portion of the steam will still be condensed and still more if a blower is made to force the air into the cistern.

The condensing hot water may be made to pass through another condenser-like apparatus, called in that case an attemperator for the purpose of warming air or water, whereby a large portion of the fuel consumed may be utilized, far more indeed than by any other means and finally the entire condensation may be produced with air or partly with air and partly with water.

It is scarcely necessary to add, that, the boiling-hot condensing water and the vapor arising therefrom are both available for cooking purposes at no cost whatever for fuel.

In conclusion I may state that a valve should be placed upon the cistern of the heater-condenser 3 to regulate the temperature, and that the amount of condensing water needed by my system of condensation will ordinarily be about four times that of the feed-water, which is only about five per cent of the amount ordinarily required for other surface condensers.

That I claim as my invention and desire to secure by Letters Patent, is-

The application of condensers, consisting of two hollow slabs connected together by concentric tubes, and communicating with each other by means of the annular spaces formed by lthem, when and at the same time, such condensers are combined with and placed in cisterns, so as to form one complete condensing apparatus, and operated in the manner and for t-he purposes as herein fully set forth and described.

THOMAS PROSSER.

Witnesses ALLEN MOORE, JOHN BOOTH.

[FIRST PRINTED 1912.] 

